everybody, that is ,except his six-year-old daughter

问题描述:

everybody, that is ,except his six-year-old daughter
这句话that is 怎么理解? six-year-old 为什么不用复数?是合成词?/////////////////////////////////////

每个人都在这里,除了他的6岁得女儿?!
six-year-old是复数合成词
含数词的复合名词作定语时,不用复数,且要用连字符